The two hotels we've reserved room blocks at in Renton are the Renton Larkspur Landing and the Hilton Garden Inn.  They are both nice hotels which cater to traveling business clientele.  The Hilton Garden Inn has a pool and a bar.  The Larkspur Landing is right across the parking lot and they send their patrons to the bar at the Hilton Garden Inn.  Both places have complimentary shuttle service to anywhere you want to go within five miles (far enough to get you to other decent - and less overpriced - restaurants and bars).  For folks who stay here, there will be ample options for carpooling to the wedding as the hotels are right next to each other.   
 
We've also reserved rooms at the Best Western Peppertree in Auburn.  The rooms there are large and nicely furnished, and it has a pool.  There's a barbecue joint next door, but not a lot else going on.  We've been told they have complimentary breakfasts on the weekend which include waffles and egg soufflés.  In case you were itching for an egg soufflé.
 
Both the Larkspur Landing and Best Western Peppertree rooms include small (and surprisingly nice) kitchenettes.   
 
All three hotels are in roughly the same $100 - $129/night range (a little more for the suites at Larkspur Landing that will sleep two couples or give more space to a family), and all rooms are released to other customers three weeks prior to the July 12th weekend, so don't wait to book. 

If you're on a tighter budget, doing a priceline search for hotels around SeaTac airport is probably a good bet (and only a little further drive). 
If you're hoping to stay within Seattle city limits, there are tons of fabulous options but they're generally on the more expensive side.  Here are a few suggestions for budget travelers: The Ace Hotel has European style rooms (read: small) with or without bathrooms that are very cute and fairly reasonable.  The Moore Hotel is a big, aging hotel for rockstars and other hipsters who haven't yet made it (great if you want an inexpensive room that still has some character, and you don't mind a little noise).  Pensione Nichols B&B is another budget spot at a great location close to Pike Place Market.  If you're looking for a fancy hotel - these are probably not it - although they all have a certain charm.  The Renton and Auburn options are much "nicer" (as in, we would happily book rooms for either of our moms in those hotels), and they're closer to the reception site.  We haven't reserved rooms at any Seattle hotels, but if you inquire now, you should still be able to find rooms available.

If you have special requirements, or questions that we haven't answered, email or call us.